Wells, such as petroleum wells, must generally be safely plugged when abandoned. This is a critical operation since both health and safety risk and potential environmental damage may result if an abandoned well is not reliably sealed off. Various statutory requirements exist in relation to how such plug and abandonment may be carried out. This is typically done by filling a section of the wellbore with a fluidized plugging material, such as cement, which will harden and create a safe, long-lasting barrier in the well.
In wells having a casing, there may be a need to ensure that the wellbore is sealed both inside and outside of the casing, i.e. also in the annulus between the casing and the formation. One prior art method of achieving this is to remove a section of the casing and to arrange a cement plug in the wellbore. Another method, in which a casing is perforated and a plugging material is placed in the casing and in the annulus is described in WO 2012/096580 A1.
In addition to the above, well operations generally require highly specialized equipment and can thus be very expensive. There is therefore a need for improved solutions which allow plugging operations to be carried out efficiently, while maintaining a high level of safety and the ability to create a reliable plug. The present invention aims to provide an improved method and system, addressing at least one of these objectives, compared to known techniques.